如何检查Flutter应用程序是否在前台? [英] How do I check if the Flutter application is in the foreground or not?

问题描述

我不想在应用程序处于前台状态时显示通知.如何查看我的应用程序的实时状态?

I don't want to show notification when the app is in foreground. How can I check live state of my app?

推荐答案

在您的State< ...>类中，您需要实现

In your State<...> class you need to implement WidgetsBindingObserver interface and listen for widget state changes. Something like this:

class _MyHomePageState extends State<MyHomePage> with WidgetsBindingObserver {
  AppLifecycleState _notification; 
  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    setState(() {
      _notification = state;
    });
  }

  @override
  initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    ...
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }
}

然后，当您想知道什么是状态时，请检查_notification.index属性._notification == null =>没有状态更改发生，0-恢复，1-无效，2-暂停.

Then when you want to know what is the state, check _notification.index property. _notification == null => no state changes happened, 0 - resumed, 1 - inactive, 2 - paused.

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